Electric resistance welder



A. L. WILLIAMS ET AL 2,908,803

ELECTRIC RESISTANCE WELDER Oct. 13, 1959 Filed April 22, 1957 3Sheets-Sheet 1 J6 g INVENTORS Z1 35 7 ARTHUR L.W\\ \AMs BY JAME$ F. DEFFNBAUGH A rrore/ve y Oct. '13, 1959 Y A. L. WILLIAMS ETAL 2,908,803

ELECTRIC RESISTANCE WELDER Filed April 22. 1957 s Sheets-Sheet 2 44 4 J!45 v I! E-\ ;\3. I

J2 J2 ,g 46

INVENTOR ARTHUR L\W\LUAM5 yJAMzs F. DEFFENBAUGH A. 1.. WILLIAMS ETAL2,908,803

ELECTRIC RESISTANCE WELDER 3- Sheets-Sheet 3 Filed April 22, 1957INVENTORS RTHUR L.W\ LLIAMS BY JAMEs F DEFFENBAUGH A 77ORNX UnitedStates Patent C) ELECTRIC RESISTANCE WELDER Arthur L. Williams and JamesF. Detrenbaugh, Warren, Ohio, assignors to The Federal Machine andWelder Company, Warren, Ohio Application April 22, 1957, Serial No.654,190

. 14 Claims. (Cl. 219-84) Our invention relates to electric resistancewelders, particularly to seam welders, and the principal object of ourinvention is to provide new and improved welders of this character.

In seam welder construction, it is necessary to conduct a current ofhigh amperage from the secondary of the welder transformer to the wheelelectrodes in as efficient .manner as possible. The problem is ofconsiderable magnitude since each wheel electrode is carried by a shaftwhich is journalled in an arm carried by the Welder frame and the armsare respectively electrically connected to opposite sides of thetransformer secondary.

For eflicient operation, the means for conducting current from an arm toa respective shaft must provide for the least amount of resistance tothe passage of current, not only to minimize the generation of heatcaused by the resistance to current flow, but also to minimize thereduction of current caused by resistance in its path of flow. At thesame time, it is necessary that the current conducting means does notestablish a serious drag on the shaft to prevent its relatively freerotation.

In the past, certain constructions have attempted to solve one or theother of the problems above noted, but none has solved all of theproblems in the efficient manner hereinafter disclosed.

Our invention also provides means for adjusting the electrode wheelsrelative to each other whereby certain machining accuracy heretoforerequired is eliminated. The adjustment means of our invention enablesthe electrode wheels to be adjusted not only in an axial direction butalso in a radial direction whereby for certain operations the wheels maybe relatively skewed to effect better welding conditions.

In the drawings accompanying this specification and forming a part ofthis application, there is shown, for purposes of illustration, anembodiment which our invention may assume, and in these drawings:

Figure 1 is a small scale, generally schematic representation of a seamwelder incorporating our invention,

- Figure 2 is an enlarged sectional view through the upper arm of thewelder shown in Figure 1, parts being shown in elevation and parts beingonly fragmentarily shown,

Figure 3 is an enlarged sectional View corresponding generally to theline 3-3 of Figure 2,

Figure 4 is a fragmentary sectional view corresponding generally to theline 44 of Figure 3,

Figure 5 is a fragmentary sectional view of parts of the upper armproviding for relative adjustment of the wheel electrodes, certain partsbeing shown fragmentary and in elevation,

Figure 6 is a fragmentary sectional view corresponding generally to theline 6--6 of Figure 5,

Figure 7 is a sectional view corresponding generally to the line 77 ofFigure 5,

Figure 8 is a separated perspective view of parts of the constructionshown in Figures 5 through 7, and

Figure 9 is a schematic representation of the wheel electrodes in skewedrelation.

Patented Oct. 13, 1959 The seam welder disclosed in Figure 1 may be ofany standard type comprising a frame 10 housing a transformer 11 in anysuitable manner. As is usual, the primary winding 12 of the transformeris adapted to be connected to a source of electrical energy and theopposite ends of the secondary 14 are respectively connected to upperand lower arms 15 and 16 of the welder.

Each arm 15 and 16 rotatably supports a shaft and the shafts carry theseam welding wheels 17 between which work is to be welded. The lower arm16 usually extends horizontally in fixed manner from the welder frame,as seen in Figure 1, while the upper arm 15 is mounted for verticalmovement toward and away from the lower arm. Movement of the upper armaway from the lower arm provides clearance between the wheel electrodes17, 17 for the insertion of the work to be welded, and movement of theupper arm toward the lower arm provides for firm engagement of the wheelelectrodes with opposite sides of the work to be welded.

The upper arm may be moved in any suitable manner, a common oneincluding a vertical slide 18 connected to said arm and slidablyreceived in a bearing 19 carried by the frame 10. A fluid motor 20provides the power for moving the upper arm. In the present disclosure,only the upper arm 15 is shown in detail but it will be appre ciatedthat our invention may also be used in connection with the lower arm.

The upper arm 15, in the present embodiment, comprises a housing 21having a welled upper portion 22 which may have suitable connection tothe slide 18. The well of the portion 22 may be closed by a cover 23 sothat cooling water may be circulated therethrough by means of pipeconnections 24. A horizontal shaft 25 is journalled within the housing21, the forward end of the shaft carrying the wheel electrode 17 and therear portion of the shaft extending outwardly of the housing, as shown.

The housing has internal annular surfaces 26, 27 into which respectivelyseat roller bearings 28, 329. Insulating sleeves 30 are disposed betweenthe bearings and the housing so that no electrical current will betransmitted through the bearings to cause deleterious pitting thereof.

The bearing seats 26, 27 have oppositely disposed shoulders 31, 32respectively and the shaft 25 has an annular shoulder 33 engaging withthe inner race of the bearing 28. Play in the bearings 28, 29 mayaccordingly be adjusted by means of a ring-type nut 34 which is threadedon the shaft 25. The weld wheel 17 is secured to the outer end of theshaft 25 in any suitable manner and the shaft and wheel may be watercooled in accordance with customary practice.

The shaft 25 may be driven in any suitable manner and, as herein shown,a worm wheel 35 is keyed to the shaft and a ring-type nut 36 is threadedonto the shaft to hold the wheel against a shaft shoulder 37. A worm 38carried by a shaft 39 journalled in the housing 21, meshes with the wormwheel 35. An electric motor, not shown, may be used to rotate the wormshaft 39.

A sub-housing 40 is connected in axial alignment to the rear end of thehousing 21, as by means of bolts 41 to provide good mechanical andelectrical connection therebetween. The housings 21 and 40 are made ofgood current conducting metal, such as cast copper or copper alloy, andlikewise the shaft 25 and weld wheel 17 are also made of good currentconducting metals which will suitably take the pressure necessary in aWelding operation. Suitable copper alloys may be used for the shaft andweld wheel. Likewise, the saddle 42 carried by the lower end of theslide 18 and to which the housing 21 is securely mechanically andelectrically connected is also made of suitable metal such as castcopper or copper alloy. Accordingly, a low resistance path isestablished for conducting electrical current from the transformersecondary, through the saddle 42, housing 21 and to the sub-housing 40.

Means are herein provided for efliciently conducting electrical currentfrom the arm (housing 21 and sub housing 40) to the shaft 25 and weldwheel 17. In the embodiment of our invention herein disclosed, aplurality of 'current conducting means 43 are radially spaced about theshaft 25 and disposed in spaces 44 between the shaft and the sub-housing40.

Each of said current conducting means is best illustrated in Figures 3and 4 and preferably comprises a flexible member 45 having one endmechanically and electrically secured to the sub-housing 40 and anopposite end free for flexing movement toward the shaft 25.

The flexible member may be formed of any suitable flexible conductormaterial, such as braided wire or ribbon, or the like, although at thepresent time it is preferred to form the member of stacked copperlaminations.- As an example, laminations of hard copper, each .005 inch,have been successfully used. The lami nations are preferablyrectangular, to form an oblong member 45, and each member is spacedlaterally from the shaft and extends generally parallel or lengthwise ofthe shaft. One end of each member is formed with atransverse aperture topass a bolt 46, the head of the bolt bearing against the innermostlamination and the end of the bolt being threaded into the sub-housing40 to mechanically and electrically secure the member 45 to thesub-housing 40. A copper spacer collar 47 may be interposed between theoutermost lamination and the inner surface of the sub-housing toproperly position the member 45 and to enhance electrical conduction.

Each lamination may be silver coated or only the inner and outermostlaminations in some instances are silver coated to provide for goodelectrical connection. The collar 47 may likewise be silver coated, ifdesired.

A copper shoe 48 is secured to the free end of each flexible member 45and mechanically and electrically held to such end by means of a machinescrew 49. The surface of the shoe which adjoins the member 45 may besilver coated to improve current conduction.

The innner surface of each shoe 48 is provided with a silver liner 50and the inner surface of the liner is arcuate and generally correspondsto the transverse curvature of the adjacent portion of the shaft 25.

Means are provided for urging the free ends of the flexible members 45in a. direction toward the shaft and in the present embodiment thesub-housing 40 is formed with a pair of threaded apertures 51 in linewith each'free end of the members 45. Socket head plugs 52 are threadedinto the apertures 51 to bear against and compress respective coilsprings 53. A sheet of insulation 54 is disposed between the coilsprings 53 and the adjacent surface of the member 45 to preventelectrical current from passing through the springs and adverselyaffecting them.

The assembly of the current conducting means 43 with the sub-housing 40may be made while the latter is removed from the housing 21 and shaft25. This, therefore, facilitates assembly operations and also provideseasily detachable means for the purpose of inspecting the condition ofthe current conducting means 43 after a considerable period of use.

An end plate 55 may be secured to the rear open end of the sub-housing40, the plate carrying a seal 56 hearing against the shaft to restrictentrance of foreign matter. A similar seal 57 may be carried by theforward end of the housing 21 to bear aganst the shoulder 33 andrestrict entrance of foreign matter at the forward end of the housing.

The current conducting means 43 are preferably ar- 4 In this manner,cocking pressure against the shaft is avoided and the shaft may freelyrotate in its bearings. Since a low resistance current path is providedby the current conducting members 43, the exceedingly great pressuresheretofore required to maintain good electrical contact are eliminatedand very little drag opposes rotation of the shaft.

Our invention also provides means for adjusting the wheel electrodes17-17 relative to each other and in the presently disclosed embodimentthe saddle 42 be,- tween the housing 21 and the slide 18 comprises aweld head support 60 and a lead connection member 61.

The weld head support 60 has a circular upper plane surface 62 and acentral boss 63 extending upwardly from such surface. The support 60 isformed with a transverse through bore 64 for passing a bolt 65 andthe'boss 63 is formed with a cross slot 66 intersecting the bore 64. Thesupport 60 is also formed With a pluralityof transverse apertures 67(four in the embodiment disclosed) for passing bolts 68.

The underside of the support 60 is formed with marginal enlargements 69,70, the enlargement 70 providing a gib surface 71 which receives acomplementary slide surface 72 formed along the side of the upperportion 22 of the housing 21. A similar slide surface 73 is formed alongthe opposite side of the portion 22 for cooperation with the angularside surface of an elongated key member 74.

The key member is interposed between the slide surface 73 andan inwardlydirected shoulder 75 formed on the enlargement 69 and, by means of bolts76 (one of which is shown in Figure 6) securely locks the housing 21against sliding movement along the gib surface 71 and the correspondingsurface of the key member 74. When the bolts 76 are loosened, thehousing 21 may be adjusted along a substantially horizontal plane in adirection defined by the gibsurfaces. It will thus be appreciated thatthe upper electrode wheel 17 may be adjusted in an axial directionrelative to the lower electrode Wheel.

Provision is also made for rotation of the upper electrode wheel in agenerally horizontal plane so that misalignment of the wheels may becorrected, or so that the wheels may be disposed in skewed relation, assuggested in Figure 9, for certain welding requirements.

In the present embodiment, the undersurface of the lead connectionmember 61 is formed with a plane surface 80 complementary to the surface62 of the weld head support 60. The surface 80 is formed with an annularwell 81 for receiving the boss 63, the upper surface of the latter beingpreferably clear of engagement with the bottom of the Well.

The member 61 is also bored to receive a sleeve 82 having a head 83. Thelower end of the sleeve 82is milled to form a key 84 which fits into thecross slot 66 of boss 63 and holds the sleeve against rotation. The bolt65 is threaded into the sleeve and the parts provide an axis about whichthe head support 60 may rotate. The lead connection member 61 is formedwith arcuate slots 85 for passing the bolts 68. Loosening of the bolts68 will permit the head support 60 to be swung about its vertical axisan amount defined by, the length of the slots 85. After adjustment, thebolts 68 may be tightened to firmly hold the head support and leadconnection 'member is axially adjusted relation.

A'sheet of electrical insulation is interposed between the upper surfaceof lead connection member 61 and slide 18, and bolts 87 are provided tomaintain the member and-slide assembled, insulating sleeves 88 beinginterposed between the bolts and the member 61. Thus, the member 61 iselectrically insulated from the slide. I The slide 18 is of non-circularcross-section and the bearing 19 will accordingly hold the slide and thelead connection member 61 against rotation about the axis provided bythe sleeve 82. As best seen in Figure 1, the member 61 has afoot 90 towhich one side of the transformer secondary may be connected.

In view of the foregoing, it will be apparent to those skilled in theart that we have accomplished at least the principal object of ourinvention and it will also be apparent to those skilled in the art thatthe embodiment herein described may be variously changed and modified,without departing from the spirit of the invention, and that theinvention is capable of uses and has advantages not herein specificallydescribed, hence it will be appreciated that the herein disclosedembodiment is illustrative only, and that our invention is not limitedthereto.

- We claim:

1 1. A resistance Welding machine, comprising a current carrying arm, acurrent carrying shaft journalled by said arm and providing an electrodewheel, and means providing for current flow between said arm and saidshaft and comprising a flexible member having one portionmechanicallyand electrically connected to said arm and a spaced portion immediatelyengaging said shaft and yieldably pressed thereagainst.

2. A resistance welding machine, comprising a current carrying arm, acurrent carrying shaft journalled by said arm and providing an electrodewheel, and means providing for current flow between said arm and saidshaft and comprising a flexible laminated member having one portionmechanically and electrically connected to said arm and a spaced portionimmediately engaging said shaft and yieldably pressed thereagainst.

3. A resistance welding machine, comprising a current carrying arm, acurrent carrying shaft journalled by said arm and providing an electrodewheel, and means providing for current flow between said arm and saidshaft and comprising a current-conducting member laterally spaced fromand disposed generally longitudinally of said shaft, one end of saidmember being mecha-.

nically and electrically connected to said arm, and means for yieldablypressing the other end of said member in a direction toward said shaft.

4. A resistance welding machine, comprising a current carrying arm, acurrent carrying shaft journalled by said arm and providing an electrodewheel, and means providing' for current flow between said arm and saidshaft and comprising a current-conducting member laterally spaced fromand disposed generally longitudinally of said shaft, one end of saidmember being mechanically and electrically connected to said arm and theOpposite end being free and having an inner arcuate surface generallycorresponding to the transverse curvature of said shaft, and meanscarried by said arm for pressing inwardly against said opposite end ofsaid current conducting member to press said arcuate surface intosliding current conducting engagement with said shaft.

5. A resistance welding machine, comprising a current carrying arm, acurrent carrying shaft journalled by said arm and providing an electrodewheel, and means providing for current flow between said arm and saidshaft and comprising a flexible current conducting member laterallyspaced from and disposed generally longitudinally of said shaft, one endof said member being mechanically and electrically connected to said armand its opposite end being free for flexing movement toward said shaftand having an inner arcuate surface generally corresponding to thetransverse curvature of said shaft, and means carried by said arm forpressing inwardly against said opposite end of said current conductingmember to press said arcuate surface into sliding current conductingengagement with said shaft.

6. A resistance welding machine, comprising a current carrying arm, acurrent carrying shaft journalled by said arm and providing an electrodewheel, and means providing for current flow between said arm and saidshaft and comprising an elongated flexible member laterally spaced fromand disposed generally longitudinally of said shaft, said member beingformed of current con- 6 ducting laminations and one end thereof beingmechani cally and electrically connected to said arm and the oppositeend being free for flexing movement toward said said shaft, a currentconducting shoe electrically connected to said opposite end of saidmember and having an inner arcuate surface generally corresponding tothe transverse curvature of said shaft, and means carried by said armfor pressing inwardly against said opposite end of said member to presssaid arcuate shoe surface into sliding current conducting engagementwith said shaft.

7. A resistance welding machine, comprising a current carrying arm, acurrent carrying shaft journalled by said arm and providing an electrodewheel, and means providing for current flow between said arm and saidshaft and comprising a block-like elongated flexible member laterallyspaced from and disposed generally longitudinally of said shaft, saidmember being formed of copper laminations and being silver coated onopposite sides, one end of said member being mechanically andelectrically connected to said arm and the opposite end being free forflexing movement toward said shaft, a copper shoe mechanically andelectrically connected to said opposite end of said member, the inwardlydirected surface of said shoe having a silver lining and the innersurface of the latter having an arcuate surface generally correspondingto the transverse curvature of said arm, a plug threaded through saidarm and having its axis intersecting said member at said opposite end,and a coil spring compressed between the inner end of said plug and saidopposite end of said member to press inwardly against said opposite endand thereby press said arcuate surface into sliding current conductingengagement with said shaft.

8. A seam welder having a low friction welding wheel mount, comprising acurrent carrying arm, a current carrying shaft supporting the weldingwheel, spaced antifriction bearings between said arm and said shaft,said bearings being electrically insulated to prevent passage of currenttherethrough, and means providing for current flow between said arm andsaid shaft comprising a plurality of flexible current conducting membersequally spaced apart radially about said shaft and disposed in a spacebetween said arm and said shaft in position spaced laterally of saidshaft, each member having one end mechanically and electricallyconnected to said arm and having its other end free for flexing movementtoward said shaft and formed with an inner arcuate surface generallycorresponding to the transverse curvature of said shaft, and meanscarried by said arm for pressing inwardly against said opposite end ofsaid current conducting member to press said arcuate surface intosliding current conducting engagement with said shaft.

9. The construction according to claim 8 and further including saidcurrent conducting members in paired opposing relation.

10. A resistance welding machine, comprising a support, a currentcarrying arm, a current carrying shaft journalled by said arm andproviding an electrode wheel, means providing for current flow betweensaid arm and said shaft, said arm having spaced slide surfaces one ofwhich is slidable along a corresponding surface of said support and theother one is slidable along a corresponding surface of a wedge-like keymember, and means for urging said key member in a direction to bind saidarm against movement relative to said support.

11. In a resistance welding machine having one electrode movable towardand away from another electrode, a mount for the movable electrode,comprising a reciprocable slide member, a lead connection member ofcurrent conducting material secured to but insulated from said slidemember for reciprocatory movement therewith and having means forconnection to one side of the secondary circuit of the weldingtransformer, a support member of current conducting material connectedto said lead connection member for pivotable movement about an axisgenerally parallel to the axis of reciprocation of said slide member, acasing member of current conducting material connected to said supportmember for slidable adjustment transverse to the axis of reciprocationof said slide member, a current carrying shaft supporting said onemovable electrode and journalled in bearings carried by but insulatedfrom said casing member, and means between said casing member and saidshaft for conductin welding current from the former to the latter.

12. In a resistance welding machine having one electrode movable towardand away from another electrode, a mount for the movable electrodecomprising a reciprocable slide member, a lead connection member ofcurrent conducting material having one side connected to but'insulatedfrom said slide member for reciprocatory movement therewith and havingmeans for connection to one side of the secondary circuit of the weldingtransformer, a support member of curernt conducting material having. oneside bearing against the opposite side of said lead connection memberand being connected to the latter for pivotable movement about an axisgenerally parallel to the axis of reciprocation of said slide member,the opposite side of said support member being formed with spaced guidegrooves extending transversely of the axis of reciprocation of saidslide member, a casing member of current conducting material havingspaced slide surfaces, one of which slidably engages the surface of oneof said spaced guide grooves and a wedge-like key member seated betweenthe other of said guide grooves and slide surfaces whereby said casingmember is held to said support member for slidable adjustment transverseto the axis of reciprocation of said slide member, means for forcingsaid wedge-like key member into locking engagement with the surfaces ofits associated guide groove and slide surface to hold said supportmember in adjusted position, a curent carrying shaft supporting said onemovable electrode and journalledin bearings carried by but insulatedfrom said casing members, and means between said casing member and saidshaft for conducting welding current from the former to the latter.

13. In a resistance welding machine having a rotatable electrode, acurrent conducting shaft supporting and electrically connected to saidelectrode, a casing through which said shaft extends and in which saidshaft is rotatably supported, said electrode extending from one side ofsaid casing and an end portion of said shaft extending from the oppositeside of said casing, an end member of current conducting materialremovably secured to the opposite side of said casing and having anopening passing said shaft end portion, said end member beingconnectable to one side of the secondary circuit of the weldingtransformer, and current transfer means for conductmg Welding currentfrom said end member to said shaft,

said transfer means being carried by said end member and assembleabletherewith when said end member is re moved from said casing, said endmember and transfer means being assembled as a unit with said casing incooperable relation with said shaft end portion.

14. In a resistance welding machine having a rotatable electrode, acurrent conducting shaft supporting and electrically connected to saidelectrode, a casing through which said shaft extends and in which saidshaft is 1'otatably supported, said electrode extending from one side ofsaid casing and an end portion of said shaft extending from the oppositeside of said casing, an end member of current conducting materialremovably secured to the opposite side of said casing and having anopening passing said shaft end portion, said end member beingconnectable to one side of the secondary circuit of the weldingtransformer, and current transfer means for conducting welding currentfrom said end member to said shaft, said current transfer meansincluding a plurality of similar flexible current conducting membersspaced from each other and grouped about the axis of said end memberopening, each conducting member having one end mechanically andelectrically connected to said end member and its opposite free endpressed into sliding electrical engagement with said shaft end portion,said current conducting members being assembleable with said end memherwhen the latter is removed from said casing and said end member andconductor members being assembled as a unit with said casing incooperable relation with said shaft end portion.

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